Every fall, many children reach a milestone - they start kindergarten. While the first day of school may bring images of a common experience, not only does kindergarten differ for children today from what we may recall as adults, it differs for children based upon where they happen to live. Here are ten facts about kindergarten as we start the 2015-2016 school year:

1. Number of children expected to enroll in kindergarten in the US in fall 2015: 3.7 million. (Source)

2. Number of children to be enrolled in prekindergarten programs: 1.3 million. In 1990, 25 years ago, 303,000 children were enrolled in public prekindergarten programs. (Source)

3. Number of states requiring school districts to offer ½ day kindergarten: 34.

4. Number of states requiring full day kindergarten: 11 plus D.C.

5. Number of states not requiring districts to offer kindergarten: 5 (Alaska, Idaho, New York, Pennsylvania; in New Jersey, only the Abbott districts must offer kindergarten). (Source)

6. Number of states requiring children to attend kindergarten: 15 states plus DC (35 do not). (Source)

7. September 1 – the most common birthdate by which children must turn 5 to be eligible to enroll in kindergarten (19 states). (Source)

8. The birth date cut-off ranges from as early as July 31 (Hawaii, Missouri, Nebraska, North Dakota) to as late as January 1 (Connecticut). (Source)

9. As of May 2014, the average salary for a kindergarten teacher was $53,480. (Source)

10. 15% of children entering kindergarten for the first time in fall 2010 spoke a language other than English as the primary language in their home (Source)